BE1028117B1 - FIRE RESISTANT OBJECTS AND STRUCTURES - Google Patents

Abstract

Article made of fire-resistant polymer foam, structure, which comprises such an article, use of the article or the structure and method for producing the article or the structure, wherein the polymer foam (a) 25 to 55% by weight of a polymer composition, which (a1) a first Polymer component which is selected from the ethylene / C1-C4 alkyl acrylate copolymers, the ethylene / vinyl acetate copolymers or mixtures thereof, (a2) a second polymer component which is selected from the copolymers which have functional maleic anhydride groups, preferably the ethylene / C1- C4-alkyl acrylate copolymers on which maleic anhydride is grafted, the ethylene / vinyl acetate copolymers on which maleic anhydride is grafted, or mixtures thereof, (a3) comprises a third polymer component which is selected from the thermoplastic polyolefins, the elastomeric polyolefins, the Ethylene homopolymers and mixtures thereof; (b) 45 to 70% by weight of a flame retardant component comprising magnesium hydroxide, aluminum hydroxide, a combination of calcium carbonate and silicone rubber or mixtures thereof, and possibly one or more nanoclay minerals; (c) 0.01 to 8% by weight of additives selected from the pigments, antioxidants, UV filters, lubricants, antistatic agents, cell formation promoting agents, cell formation inhibitors, infrared wave reflecting / absorbing agents, heat stabilizers and / or metal deactivators; The polymer foam article has undergone chemical and / or physical crosslinking, the density of the foam is in the range from 700 to 1,000 kg / m3 and the percentages by weight refer to the polymer foam article.

Description

FIRE RESISTANT OBJECTS AND STRUCTURES Technical field

The present invention relates to fire-resistant or flame-retardant objects and structures that can be used in numerous fields, in particular for fire protection purposes in the building or automotive sector, for example a shell or a plate made of foam, which serves to prevent a line, a Surface catches fire. State of the art

The fire behavior and in particular the fire resistance are essential parameters that must be taken into account when developing a material. This applies in particular to organic materials such as plastics, types of rubber, organic fibers or textiles, as they are used in many areas due to their numerous advantageous physical and technical properties. It is well known, however, that these materials are generally flammable and, by their very nature, are often insufficiently fire resistant. In order to be able to use them for many purposes, they have to be modified in such a way that they prevent or at least delay the development of fire, that is to say that their fire resistance is improved.

Numerous approaches to improving the fire resistance and fire behavior are known for such materials. In particular, consideration was given to using additives such as flame retardants in these materials, if possible, or, within the scope of the given possibilities, to provide additional external protection made of non-inflammable or even non-inflammable materials of an inorganic nature.

An addition of flame retardants to the material is conceivable in the case of thermoplastic or thermosetting polymer compositions, there are in fact numerous approaches of this type with more or less good performance characteristics. There are several types of flame retardants, including compounds of a mineral nature, halogen-containing compounds or phosphorus-containing compounds.

Although some of these compounds make it possible to significantly improve the fire behavior of polymers, on the other hand they have disadvantages. For example, many of the halogen-containing compounds already have a high toxicity per se. In addition, halogen-containing compounds comprising aromatic rings can break down into dioxins and dioxin-like compounds when they are heated, for example during manufacture, during a fire, during recycling or even when exposed to the sun.

In addition, the addition of these agents to a composition changes its physical properties and can even cause the modified composition to no longer be suitable for the intended use.

The idea of an external protection that intrinsically has good fire resistance properties, since it is naturally difficult to ignite or not at all, can unfortunately rarely be implemented in practice because the available materials of this type are very often exactly the desired properties of flexibility, ease of machining, low weight, advantageous cost, etc. are lacking.

Although approaches to a solution already exist, it thus appears of interest to develop alternative materials that have good properties when exposed to fire, or to develop objects that make it possible to improve the properties of the fire resistance of existing materials.

Object of the invention

It is an object of the present invention to provide articles and structures which have good fire resistance or fire resistance which can be used in a wide variety of fields, particularly construction and the automotive sector. General description of the invention

In order to achieve the above object, the invention provides, according to a first aspect, an article made of fire-resistant polymer foam, the polymer foam comprising a) 25 to 55% by weight of a polymer composition comprising al) a first polymer component , which is selected from the ethylene / C1-C4 alkyl acrylate copolymers, the ethylene / vinyl acetate copolymers or mixtures thereof, a2) a second polymer component, which is selected from the ethylene copolymers which have functional maleic anhydride groups, preferably the ethylene / C1-C4 Alkyl acrylate copolymers on which maleic anhydride is grafted, the ethylene / vinyl acetate copolymers on which maleic anhydride is grafted, or mixtures thereof is selected, a3) a third polymer component, which is selected from the thermoplastic polyolefins, the elastomeric polyolefins, the ethylene homopolymers and the mixtures of which is selected, b) 45 to 70% by weight of a fla hardening component, which comprises magnesium hydroxide, aluminum hydroxide, a combination of calcium carbonate and silicone rubber or mixtures thereof and possibly one or more nanoclay minerals, c) 0.01 to 8% by weight of additives, including pigments, antioxidants, UV filters, lubricants, Antistatic agents, agents that promote cell formation, agents that inhibit cell formation,

Infrared wave reflecting / absorbing agents, heat stabilizers, metal deactivators, ..., whereby the polymer foam article has undergone chemical and / or physical crosslinking, the density of the foam is in the range of 700 to 1,000 kg / m * and the weight percentages are based on weight of the polymer foam article (the sum of all components making up 100% by weight of the polymer foam article).

In search of a solution that combines thermal and / or sound insulation properties with proper fire resistance characteristics, the inventors have found that it is not only possible to obtain polymer foams of appropriate density and structure with high levels of mineral flame retardants , but that the compositions given above have above all a fire resistance or flame resistance which is clearly superior to that of known compositions, and is even similar to these when the latter are in the non-foamed (i.e., dense) state. As the examples and the discussion below show, the results obtained are not only astonishingly good, but also do not meet the expectations of the person skilled in the art.

The first polymer component at) is selected from the ethylene / C1-Ca-alkyl acrylate copolymers and the ethylene / vinyl acetate copolymers, that is, the ethylene copolymers, which methyl acrylate (EMA), ethyl acrylate (EEA), propyl acrylate ( EPA) or butyl acrylate (EBA) or vinyl acetate (EVA) as a comonomer. This comonomer preferably makes up 5 to 40% by weight, in particular 10 to 35% by weight, in particular 14 to 30% by weight, particularly preferably 16 to 25% by weight, of the weight of these copolymers. The melt flow index (MFI, melt flow index, or MFR, melt flow rate) of the first component is generally between 0.01 and 20 g / 10 min., Preferably between 2 and 10 g / 10 min. (190 ° C, 2nd , 16 kg).

The amount of the first polymer component al) in the article according to the invention will in most cases be between 5 and 35% by weight, in particular 7.5 to 30% by weight, in particular 10 to 25% by weight, by weight of the 5 polymer foam article.

The second polymer component a2) is selected from the copolymers which have functional maleic anhydride groups. They can be copolymers of one or more monomers which comprise maleic anhydride groups in the polymer chain or as lateral (grafted) groups. The other monomer unit (s) are, for example, ethylene, C1-C4-alkyl acrylates, vinyl acetate, etc. The second polymer component preferably comprises ethylene / C1-C4-alkyl acrylate copolymers to which maleic anhydride is grafted, ethylene / vinyl acetate Copolymers to which maleic anhydride is grafted, or mixtures thereof, or consists of them. The content of maleic anhydride groups is generally in the range from 0.1 to 10% by weight, in particular from 0.5 to 5% by weight, in particular from 1 to 4% by weight, based on the total weight of these copolymers. The melt flow index (MFI or MFR) of the second component a2) is generally between 0.15 and 200 g / 10 min., In particular between 0.5 and 100 g / 10 min., Preferably between 1 and 20 g / 10 min. (190 ° C, 2.16 kg).

The second polymer component a2) generally makes up between 2 and 40% by weight, in particular 3 to 30% by weight, in particular 4 to 25% by weight, of the weight of the polymer foam article.

The third polymer component a3) is selected from thermoplastic polyolefins (TPO), elastomeric polyolefins (EPO), ethylene homopolymers and mixtures thereof. The EPO and TPO are copolymers of ethylene with other olefins, which are between linear low density polyethylene (LLDPE) and the completely amorphous elastomers in terms of both their density and their crystallinity. The density of the EPO is generally between 0.86 and 0.89 and that of the TPO is generally between 0.89 and 0.91 kg / m 2.

These polymers can be obtained by coordinative copolymerization of ethylene in the presence of a relatively long-chain α-olefin (1-butene, 1-hexene, etc.), for example by catalysis with a metallocene. The approximate composition of α-olefin comonomer is typically in the range of 10 to 30% by weight. Compared to LLDPE, the TPO and EPO have a flexural modulus, tensile strength, and melting point that are lower; they show an elongation value (which can be more than 800%) and a toughness which are increased (Harutun G. Karian, Handbook of polypropylene and polypropylene composites, pp. 201-204, Marcel Dekker, 2nd ed. 2009, 670 p .). The ethylene homopolymers are made from the very low density polyethylenes (VLDPE), the linear low density polyethylenes (LLDPE, linear low-density polyethylene), the linear low density polyethylenes with metallocene catalysis (mLLDPE, metallocene linear low) -density polyethylene), the low-density polyethylene (LDPE, low-density polyethylene), the medium-density polyethylene (MDPE, medium-density polyethylene) and the high-density polyethylene (HDPE, high-density polyethylene). The melt flow index (MFI or MFR) of the third component a3) is generally between 0.15 and 30 g / 10 min., In particular between 0.2 and 20 9/10 min, preferably between 0.3 and 10 g / 10 min . (190 ° C, 2.16 kg). The amount of the third component a3) depends on the amount of the components a1) and a2) in such a way that the sum of the amounts of a1) + a2) + a3) makes up 30 to 55% by weight of the weight of the polymer foam article, however, the amount of a3) is at least 0.5% by weight.

The flame retardant component b) comprises aluminum hydroxide (decomposition: 220 ° C), magnesium hydroxide (decomposition: 330 to 350 ° C) and / or a combination of calcium carbonate and silicone rubber. The flame-resistant hydroxide components act in particular in such a way that they release water at high temperatures. These components are generally in the form of hydroxide particles which have been precipitated in such a way that they have a high specific surface area, the mean diameter of the particles being less than 30 μm and preferably in

Range from 0.1 to 10 µm. These particles can optionally be coated with organic substances so that they are better compatible with the polymer components. The addition of mineral additives, as is the case with the flame-retardant component of the present invention, significantly affects the foaming, not only because the particles act as nucleating agents (gas cell-forming agents), but above all because of their large amount. When the flame retardant component of calcium carbonate in combination with silicone rubber is exposed to fire, it forms an intumescent system in which the ethylene copolymers and the carbonate decompose to form a carbon foam and the silicone decomposes to form a glass, which stabilizes the carbon foam. According to the invention, appropriate foaming is made possible in particular by using an appropriate amount of the second polymer component a2), which acts as a mediator between the polymer phase and the mineral phase, and, on the other hand, by using an appropriate amount of the polymer component a3), by means of which the effects of the high content of mineral substances on the structural and mechanical properties can be counteracted.

In an advantageous form of the invention, the proportion of flameproofing component of up to 10% by weight of nanoclay minerals can be formed, preferably from 0.1 to 6% by weight and in particular from 1 to 5% by weight, below Refers to the weight of the polymer foam article. It is desirable to use the nanoclay minerals in finely divided form, for example in the form of particles, the mean diameter of which is at most 30 μm and is preferably in the range from 0.001 to 10 μm. Examples of useful nanoclay minerals are in particular the natural or modified montmorillonites, which are modified, for example, with quaternary ammonium salts, such as CLOISITE 20A (Southern Clay Products, USA), the natural or modified hectorites, for example DRAGONITE-HP (Applied Minerals), etc.

The article made of polymer foam comprises as component c) 0.01 to 8% by weight, preferably 0.1 to 5% by weight, in particular 0.5 to 3% by weight of additives, which in particular from the volume stabilizing agents, the antioxidants, the UV filters, the antistatic agents, the dyes and pigments, the fillers, the anti-fogging agents, the antiblocking agents, the cell size regulators, the lubricants, and possibly other fire retardants (i.e. different from those of the flame-retardant component b ) differentiate).

Of the volume stabilizing agents that are useful in connection with the invention, the fatty acid amides, which include, for example, stearamide, palmitamide, behenamide and mixtures thereof, the corresponding fatty acid amines, the esters of glycerol and fatty acids, for example the alpha-, beta-monoesters with fatty acids, the diesters with fatty acids, the triesters with fatty acids, the fatty acids comprising chain lengths from Cs to C22 of a saturated or unsaturated type, and mixtures thereof, etc. to be mentioned.

Further additives include the pigments, the antistatic agents, the cell formation-promoting agents, which include, for example, talc, silicon dioxide, calcium carbonate, the cell formation-inhibiting agents, which include, for example, the oxidized polyolefin waxes, the mediating polar resins (different types than those of component a2 )), whereby these include, for example, the ionomers, the glycidyl methacrylate copolymers, etc., the infrared wave reflecting / absorbing agents, including, for example, aluminum flakes, steel flakes, carbon black, carbon in graphite form, the process and application-related antioxidants, the process and application-related Heat stabilizers, the UV absorbers / deactivators, the metal deactivators, the lubricants, including, for example, the fluoropolymer derivatives, the amides, boron nitride, the silicones, the stearates, the polyolefin waxes, and the mixtures of one or more of the Z mentioned additives.

As part of component c), additional fire protection means (of a different type than component b)) can be provided. In the present case it can be advantageous to additionally use organophosphorus-containing molecules (e.g. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) or its derivatives), sulfenamides and mixtures thereof.

Depending on the field of application of the article made of polymer foam, and in particular its desired shape, the melt flow index (MFI or MFR) of the overall composition of the article, that is, the entirety of components a), b) and c), is generally on one The value is set between 0.5 and 50 g / 10 min., Preferably between 1 and 30 g / 10 min, in particular between 1.5 and 25 g / 10 min. (190 ° C., 2.16 kg). This adjustment can be made in a relatively simple manner by varying the proportion of the third polymer component in relation to the first and second polymer components within the limit values of the total content of the article of polymer composition.

The selection of the foaming agent for the manufacture of the polymer foam article is not of critical importance. In principle, all foaming agents that are conventionally used for foaming thermoplastic or elastomeric polymers, such as physical foaming agents, in particular foaming gases such as straight-chain, branched or cyclic C2-Cs-alkanes, in particular isobutane, isopentane, are suitable for the purposes of the present invention , Neopentane, n-pentane, cyclopentane, etc., inert gases, in particular nitrogen, CO: or argon, partially fluorinated hydrocarbon compounds (PFCs) or others such as water or ethanol (if these are compatible with any crosslinking (auxiliary) agent present), dimethyl ether, etc. These physical agents can be introduced into the extruder in a gaseous, liquid, or liquefied (pressurized) state. The foaming agent (s) can furthermore be chemical foaming agents, solid or liquid, which at least partially decompose under the action of heat. They can be introduced into the feed opening of the extruder or injected / metered in at a certain distance from it. These chemical agents are, for example, sodium carbonates, citric acid or a combination thereof, azodicarbonamide, azo-bis-isobutyronitrile, dinitrosopentamethylenetetramine, 4,4'-oxy-bis (benzenesulfonylhydrazide), diphenylsulfone-3,3'-disulfohydrazide, benzene- 1,3-disulfohydrazide, p-toluenesulfonyl semicarbazide, etc .; or they comprise, according to all well-known implementation forms of the prior art, optionally processes of extrusion and / or keeping the pressure under pressure with subsequent relaxation and / or heating, etc. The foaming agents furthermore comprise syntactic means, in particular = expandable microspheres, for example EXPANCEL (Nouryon).

It should be noted that in connection with the invention, certain means that are required for foaming, not (or not as such) remain in the article made of polymer foam (especially after complete degassing), while others partially or in a modified form can remain in the article made of polymer foam, which is due, for example, to the decomposition of chemical foaming agents. As far as their content is concerned, these components are assigned to the additive component cc), unless expressly stated otherwise.

According to the invention, the foam from which the article is made of polymer foam has been crosslinked chemically and / or physically. In the production of the article from polymer foam, foaming can be started when the (co) polymer (s) is / are already in a partially crosslinked state. This measure makes it possible, for example, to increase the viscosity of the composition or even to influence the uniformity and fineness of the cell structure, which is ultimately obtained. In this case, the crosslinking can continue during the foaming, and possibly beyond.

Nonetheless, the crosslinking can also be started during or even after the foaming (especially if a physical blowing agent, i.e. one whose effect occurs upon relaxation, such as isobutane, in conjunction with a suitable crosslinking agent, for example with silane, present).

Silane and / or peroxide compounds should be mentioned as optional crosslinking component d). Vinylsilanes, in particular the vinylalkoxysilanes such as vinyltrimethoxysilane (VTMOS) or vinyltriethoxysilane (VTEOS), the allylalkoxysilanes such as allyltrimethoxysilane (ATMOS) or allyltriethoxysilane (ATEOS), the 3-methacryloxypropyltrialkoxysilane (ATEOS), the 3-methacryloxypropyltrialkoxysilane, etc., the 3-methacryloxypropyltrialkoxysilane are preferred, the 3-methacryloxypropyltrialkoxysilane, etc., the 3-methacryloxypropyltrialkoxysilane, etc., the 3-methacryloxypropyltrialkoxysilanes are preferred It is desirable to graft the silane (s) onto the polymeric resin (s) of the foamed composition, it is desirable to introduce a suitable peroxide which allows the vinylsilane molecules to react with the residues such as those from the peroxide on the or the Polymer chain (s) are formed to enter into a graft connection. Agents which increase the effectiveness of the grafting can be used, for example zinc oxide (ZnO). In order to initiate the crosslinking reaction, it is essential that water is present. The water reacts with the silane groups to form silanol groups. The latter can, under appropriate temperature conditions, condense and create bridges between adjacent chains which are provided with silanol groups. In order to significantly reduce the time required for the condensation of the silanol groups to form siloxane bonds (Si-O-Si), it is advantageous to use crosslinking catalysts such as dioctyl bis [(1-oxododecyl) oxy] stannane, dibutyltin or dioctyltin dilaurate, Dodecylbenzenesulfonic acid, etc. or mixtures thereof are added. It is useful to provide additives which make it possible to control the level of moisture present in the composition so as to prevent premature crosslinking of the same. These additives react faster with the water than the silanes to be crosslinked ("scorch retarders"). Examples include zinc oxide (ZnO) and n-octyltriethoxysilane. For the same reason, care should be taken to dry the components of the formulation sufficiently so that the amount of moisture that is present during extrusion is limited and premature crosslinking in the extruder is avoided.

Of the peroxides that are useful for crosslinking, for example, dicumyl peroxide (DCP), α, 0'-bis (t-butylperoxy) -1,3-diisopropylbenzene, 2,5-dimethyl-2,5- di-tert-butylperoxyhexane (HXA) etc., or mixtures thereof, should be mentioned. They attack the polymer chain (s) at certain points (double bonds, tertiary carbon atoms, ...), whereupon a free electron is formed that can combine with that of an adjacent chain to create a cross-linking bridge (bond). to create between the chains.

The foam can advantageously contain crosslinking auxiliaries as (part of the) crosslinking component, in particular trimethylolpropane trimethacrylate (TMPTMA), triallyl isocyanurate (TAIC), ...

It is important to point out that in connection with the invention, the statement that the article contains the crosslinking components d) mentioned, in fact means that the (finished) article has undergone crosslinking in the presence of these compounds, which , depending on their nature and function, have decomposed, have been released or have become completely or partially part of the article made of polymer foam.

As a variant, or in addition, the semi-finished object can be subjected to (additional) crosslinking by exposing it to high-energy UV radiation which, depending on the thickness of the object to be crosslinked, is of the beta or gamma type. The dose of beta or gamma radiation that is used in each case will generally be 50 to 200 kGy, in particular 100 to 150 kGy, the irradiation preferably being carried out in such a way that the object made of polymer foam is brought to a certain temperature, especially at a temperature of the object from 100 to 230 ° C, for example from 150 ° C to

200 ° C. However, it is necessary to remain sufficiently far away from the melting temperature of the foamed composition so that the object does not deform under the influence of its own weight, overhanging portions, ...

In a second aspect the invention provides a fire protection structure comprising a fire resistant polymer foam article according to the present invention. The structure can be a planar structure, preferably a fire protection panel in construction or in the automotive sector, the fire protection panel being suitable for being applied to surfaces to be protected, such as walls of buildings or body surfaces. As a variant, the fire protection structure has a tubular shape, which is preferably a fire protection cover in the building industry or in the automotive sector. Such a fire protection cover is suitable for being attached (separately) to cables and lines, in particular to lines for flammable fluids, whereby it is intended in particular for fuel lines. In this variant, the shell is a structure that is separate from the element it is intended to protect and is used after the element in question has been manufactured. If necessary or desired, however, the structure can also be attached to the element to be protected, for example by gluing or heat fusing, etc.

In another variant, the fire protection structure is a tubular structure which forms an external fire protection layer on cables and lines in construction or in the automotive sector, in particular on lines for flammable fluids, and is intended in particular for fuel lines. In these variants, and in contrast to the previous variant, the structure is an integral part of the element which it protects, whereby it is generally applied during the production of the element, for example by process-integrated extrusion or by coextrusion.

A third aspect relates to the use of a fire-resistant article made of polymer foam or a fire protection structure according to the invention as a fire protection element in construction or in the automotive sector. It is preferably a fire protection plate that is attached to surfaces to be protected, such as the walls of buildings or bodywork, walls of electrical batteries, or a fire protection cover that is attached to cables and lines to be protected, in particular to lines for flammable fluids, particularly intended for fuel lines.

The invention further relates, in a fourth aspect, to a method for producing a fire-resistant article from polymer foam, the method comprising the following steps: (i) metering in components a1), a2), a3), b), c ) and optionally d), in premix or as single doses, into the feed device of an extruder; (it) softening and mixing the ingredients at high temperature to melt and homogenize these ingredients; (ii) homogenizing the ingredients; (iv) cooling the mass; (v) extruding under ambient air through a temperature controlled nozzle having a predetermined cross-sectional shape, thereby causing the formation of a polymeric foam; (vi) cooling the polymer foam thus formed to form a fire-resistant polymer foam article; wherein the foaming either by means of one or more chemical foaming agents that are present in the premix in step (i) and / or (ii) or are metered in, or by supplying or introducing a physical foaming agent in step (i), in step (ii) or between steps (ii) and (ill), or by a combination of both; and wherein the crosslinking of the polymer foam either chemically in the presence of

Component d) or by physical means by exposure to high-energy radiation, preferably of the UV-alpha or UV-beta type, or by a combination of both.

The method can furthermore comprise, during step (vi), before cooling, the action of pulling and guiding means on the foam after it has been formed.

In these processes, the chemical foaming agent (s) is / are generally composed of the solid or liquid chemical foaming agents, preferably sodium carbonates, citric acid or a combination thereof, azodicarbonamide, azo-bis-isobutyronitrile, dinitrosopentamethylenetetramine, 4,4-oxy-bis - (benzenesulfonylhydrazide), diphenylsulfone-3,3 "-disulfohydrazide, benzene-1,3-disulfohydrazide, p-toluenesulfonylsemicarbazide, or combinations thereof; and / or from the liquid or gaseous physical foaming agents, preferably the straight-chain, branched or cyclic Cz- Cs-alkanes, in particular isobutane, isopentane, neopentane, n-pentane, cyclopentane, the inert gases, in particular nitrogen, CO2 or argon, the partially fluorinated hydrocarbon compounds, water, ethanol, dimethyl ether, or combinations thereof.

The thickness of the polymer foam in the objects and structures according to the invention is generally in the range from 0.5 mm to 10 cm, or even more, depending on the area of application. In the case of protective applications in the form of a sleeve or tube or in the form of a tubular layer which is part of the element to be protected, the thickness of the polymer foam, when measured according to the direction of the radius of the cross section of the tube or sleeve, is typically 0, 5 to 50 mm, preferably 1 to 10 mm, particularly preferably 2 to 5 mm. In the case of applications in planar form, for example as a plate, the thickness of the polymer foam, if it is measured at right angles or in a tangential direction to the plane of the layer of polymer foam, is

typically 0.5 mm to 15 cm, preferably 5 mm to 5 cm, particularly preferably 2 to 25 mm.

In connection with the invention, the term "fire resistance" or "fire-resistant" means that the foam or the article on the one hand the spread of a flame through the foam or the article delayed over a period of time that is significantly longer than when crossing one equivalent foam or article made of olefinic polymers without component b). On the other hand, these expressions also mean that the foam or the object retards the propagation of a flame through the foam or the object over a period of time which is considerably longer than when passing through a completely identical or similar object which has the same mass, but is not foamed. The fire-resistant polymer foam articles of the invention thus have a high level of flame retardancy, and the term "fire-resistant" is synonymous with "flame retardant".

In connection with the invention, the melt flow index (MFI or MFR) is measured in accordance with the ASTM D1238 standard. The percentages by weight of the polymer components, the flame-retardant components, the additives and, if appropriate, the crosslinking components always relate to the total weight of the polymer foam article, that is, to the entirety of components a), b), c) and optionally d). The percentages by weight of the (co) monomers in a polymer relate only to the weight of the polymer in question. Examples

Compositions according to the invention, which can be extruded and crosslinked according to the method described above to give fire-resistant polymer foam articles, comprise the following components (wherein the amounts for each of the components can be varied within the stated ranges, provided that a) + b) + C) + d) = 100% by weight of the item): Component Breakdown Amount Polymers Amount AE | ee a) polymer component, of which al) | EMA, EEA, EPA, EBA 5 to 35 and / or EVA a2) | EBA-g-MAH and / or EVA-g- 2 to 40

MAH a3) | EPO and / or EPO and / or 20.5

PE al) + a2) + a3) = b) Magnesium and / or 45 to 70 aluminum hydroxide (s) and / or a combination of calcium carbonate and silicone rubber, and possibly nanoclay mineral (s) N (messe | | vbs | d) crosslinking components 0 , 2 to 8 ee ee total | 100

Particularly advantageous compositions according to the invention, which can be extruded and crosslinked according to the method described above to give fire-resistant polymer foam articles, comprise the following components (the amounts for each of the components being able to be varied within the specified ranges, with the proviso that a) + b) + c) + d) = 100% by weight of the item): Component Breakdown Amount Polymers Amount AE | ee a) polymer component, of which al) | EMA, EEA, EPA, EBA 14 to 25 and / or EVA a2) | EBA-g-MAH and / or EVA-g- 3.5 to 10

MAH a3) | EPO and / or EPO and / or 0.9 to 15

PE a1) + a2) + a3) 25 to 40 b) Magnesium and / or aluminum hydroxide (s) and / or a combination of calcium carbonate and silicone rubber, as well as possibly nanoclay mineral (s) Bee d) Crosslinking components

SA | Total) 100)

[0044] Concrete examples of polymer foam articles according to the invention have the following composition: Component | Breakdown Quantity ee A a ee LE Se | | vies | [wwe | | 5w8 | eee | RE | Premix of LDPE and cell formation-promoting 2.8 [one mm premix of LDPE and pigment 0.1 | emma TE concentrate made from 70% GMS | Antistatic 0.1 (ATMER 122 from CRODA) in% of EVA d) (and c)) premix of porous 2.3 PTE one een 1

+ Grafting peroxide + crosslinking catalyst + antioxidants

On the basis of these compositions, test pieces of tubular casings were extruded and crosslinked according to the method described above:

The test for fire resistance was generally carried out in accordance with the DIN 73379 standard, with an exposure of at least 4 minutes to a flame at 800 ° C., with a line in which water flowed under a pressure of 1.5 bar. The test is deemed to have been passed if no leak is found within the period of 4 minutes.

Sleeves made of cross-linked foam, inner diameter = 8.5 mm. E.g. together- density wall thickness | Result set kg / m3 (mm) (measured time) (incomplete) 1 EBA +60% 800 to 1.2> 4 min, test Mg (OH) 2,850 completed, passed 2 EBA + 60% 730 4> 8 min., test Mg (OH) 2 completed, passed 3 EBA + 30% 830 4 0.54 s, test (comparison) | Mg (OH) a failed 4 EBA + 60% 780 4> 8 min., Examination Mg (OH) 2 finished, passed

EBA +33% 500 4 1.11 s, test (comparison) | Mg (OH) a failed EBA + 60% 730 4> 8 min., Test Mg (OH) 2 + completed, silane passed 7 EBA + 0% 830 4 1.11 s, test (comparison) | Mg (OH) a failed

A second series of tests for fire resistance has been carried out according to the standard DIN 73379, with an exposure of at least 4 minutes to a 800 ° C +/- 50 ° C flame, with a line in which water under a pressure of 5 bar flowed. The test is deemed to have been passed 5 if no leak is found within the period of 4 minutes.

Sleeves made of cross-linked foam, inner diameter = 8.5 mm. E.g. together- density wall thickness | Result set kg / m3 (mm) (measured time) (incomplete) 2> 6 min., Test finished, passed 1> 8 min;, test finished, passed

Claims (16)

PATENT CLAIMS 1. Article made of fire-resistant polymer foam, wherein the polymer foam comprises a) 25 to 55% by weight of a polymer composition which comprises a) a first polymer component which is made up of the ethylene / C1-C4-alkyl acrylate copolymers, the ethylene / vinyl acetate Copolymers or mixtures thereof is selected, a2) a second polymer component which is selected from the ethylene copolymers which have functional maleic anhydride groups, preferably the ethylene / C1-C4-alkyl acrylate copolymers to which maleic anhydride is grafted, the ethylene / vinyl acetate copolymers which maleic anhydride is grafted or mixtures thereof is selected, a3) a third polymer component selected from thermoplastic polyolefins, elastomeric polyolefins, ethylene homopolymers and mixtures thereof, b) 45 to 70% by weight of a flame-retardant component, the magnesium hydroxide, aluminum hydroxide, a combination of calcium carb onate and silicone rubber or mixtures thereof and possibly one or more nanoclay minerals, c) 0.01 to 8% by weight of additives, including pigments, antioxidants, UV filters, lubricants, antistatic agents, cell formation promoting agents, cell formation inhibitors, infrared wave reflecting / absorbing agents , Heat stabilizers and / or metal deactivators, the polymer foam object having undergone chemical and / or physical crosslinking, the density of the foam in the range from 700 to 1,000 kg / m? and the percentages by weight are based on the weight of the polymer foam article. 2. Fire-resistant article made of polymer foam according to claim 1, the crosslinking in the presence of d) 0.2 to 8% by weight of a crosslinking component, which is a chemical crosslinking agent, which is preferably composed of the organic peroxides, the vinylsilanes, the allylsilanes, the methacryloxypropylsilanes or mixtures of which is selected; and / or comprises a crosslinking auxiliary which is preferably selected from trimethylolpropane trimethacrylate, triallyl isocyanurate, zinc oxide or mixtures thereof. 3. Fire-resistant polymer foam article according to claim 1 or 2, wherein the first polymer component a1) is between 5 and 35% by weight, in particular 7.5 to 30% by weight, in particular 10 to 25% by weight, of the weight of the polymer foam article matters; wherein the first polymer component a1) comprises 5 to 40% by weight, in particular 10 to 35% by weight, in particular 14 to 30% by weight, particularly preferably 16 to 25% by weight, of C1-Ca-alkyl acrylate groups or vinyl acetate groups, referring to the weight of the first component; and / or where the melt flow index of the first component a1) is between 0.1 and 20 g / 10 min., preferably between 2 and 10 g / 10 min., if the measurement is at 190 ° C., 2.16 kg, according to FIG ASTM D1238 standard is carried out. 4. Fire-resistant polymer foam article according to any one of the preceding claims, wherein the second polymer component a2) makes up between 2 and 40% by weight, in particular 3 to% by weight, in particular 4 to 25% by weight, of the weight of the polymer foam article; wherein the second polymer component a2) comprises 0.1 to 10% by weight, in particular 0.5 to 5% by weight, in particular 1 to 4% by weight, of 30 maleic anhydride groups, with reference to the weight of the second polymer component; and / or wherein the melt flow index of the second component a2) is between 0.15 and 200 g / 10 min., in particular between 0.5 and 100 g / 10 min., preferably between 1 and 20 g / 10 min., if the Measurement is carried out at 190 ° C., 2.16 kg, in accordance with the ASTM D1238 standard. 5. Fire-resistant article made of polymer foam according to any one of the preceding claims, wherein in the third component a3) the density of the elastomeric polyolefins is between 0.86 and 0.89 kg / m? and that of the thermoplastic polyolefins is between 0.89 and 0.91 kg / m ?; and / or where the melt flow index of the third component a3) is between 0.15 and 30 g / 10 min., in particular between 0.2 and 20 g / 10 min., preferably between 0.3 and 10 g / 10 min., when the measurement is made at 190 ° C, 2.16 kg, according to the ASTM D1238 standard. 6. Fire-resistant polymer foam article according to any one of the preceding claims, wherein the flame-retarding component b) contains up to 10% by weight of nanoclay mineral (s), preferably 0.1 to 6% by weight and in particular 0.5 to 5% by weight %, with reference to the weight of the polymer foam article, the nanoclay minerals preferably being montmorillonites or hectorites, modified or unmodified. 7. Fire-resistant polymer foam article according to any one of the preceding claims, further comprising at least one additive selected from the volume stabilizers, the antioxidants, the UV filters, the antistatic agents, the dyes and pigments, the fillers, the anti-fogging agents, the antiblocking agents, the permeability modifiers, the cell size regulators, the lubricants and possibly further fire retardants which differ from the flame-retardant component b). 8. A fire resistant polymer foam article according to any one of the preceding claims, which is a fire resistant foam sheet or shell. A fire protection structure comprising a polymer foam fire resistant article according to any one of the preceding claims. 10. Fire protection structure according to claim 9, wherein it is a flat structure, preferably a fire protection panel in the building industry or in the automotive sector, the fire protection panel being suitable for being attached to surfaces to be protected, such as walls of buildings or body surfaces. 11. Fire protection structure according to claim 9, wherein it is a tubular structure, preferably a fire protection cover in the building industry or in the automotive sector, wherein the fire protection cover is suitable to be attached to cables and lines, in particular lines for flammable fluids, wherein it is intended in particular for fuel lines. 12. Fire protection structure according to claim 9, wherein it is a tubular structure which forms an external fire protection layer on cables and lines in the building industry or in the automotive sector, in particular on lines for flammable fluids, it being intended in particular for fuel lines. 13. Use of a fire-resistant polymer foam article according to any one of claims 1 to 8 or a fire protection structure according to claim 10 as a fire protection element in construction or in the automotive sector, preferably as a fire protection panel intended to be placed on surfaces to be protected, such as walls of buildings or To be attached to body surfaces, walls of electric batteries, or as a fire protection cover, which is intended to be attached to cables and lines to be protected, in particular lines for flammable fluids, being particularly intended for fuel lines. 14. A method for producing a fire-resistant polymer foam article according to any one of claims 1 to 8, the method comprising the following steps: (i) metering in components a1), a2), a3), b), c) and optionally d ), in premix or as single doses, into the feed device of an extruder; (ii) softening and mixing the ingredients at high temperature to melt and homogenize these ingredients; (ii) homogenizing the ingredients; (iv) cooling the mass; (v) extruding under ambient air through a temperature controlled nozzle having a predetermined cross-sectional shape, thereby causing the formation of the polymeric foam; (vi) cooling the polymer foam thus formed to form a fire-resistant polymer foam article; wherein the foaming either by means of one or more chemical foaming agents that are present in the premix in step (i) and / or (ii) or are metered in, or by supplying or introducing a physical foaming agent in step (i), in step (ii) or occurs between steps (ii) and (iii), or by a combination of both; and wherein the crosslinking of the polymer foam takes place either chemically in the presence of component d) or physically by exposure to high-energy radiation, preferably of the UV-alpha or UV-beta type, or by a combination of both. 15. The method according to claim 14, wherein step (vi) further comprises the action of pulling and guiding means on the foam after it has been formed. 16. The method according to claim 14 or 15, wherein the chemical foaming agent (s) from the solid or liquid chemical foaming agents, preferably sodium carbonates, citric acid or a combination thereof, azodicarbonamide, azo-bis-isobutyronitrile, dinitrosopentamethylene tetramine, 4,4-oxy-bis- (benzenesulfonylhydrazide), diphenylsulfone-3,3 "-disulfohydrazide, benzene-1,3-disulfohydrazide, p-toluenesulfonylsemicarbazide, or combinations thereof; and / or from the liquid or gaseous physical foaming agents, preferably the straight-chain, branched or cyclic = Cz- Cc-alkanes, in particular isobutane, isopentane, neopentane, n-pentane, cyclopentane, the inert gases, in particular nitrogen, CO2 or argon, the partially fluorinated hydrocarbon compounds, water, ethanol, dimethyl ether, or combinations thereof, is / are selected.